A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.

ubuntu_linux USN-8913-1: Ubuntu 14.04 LTS / Ubuntu 16.04 LTS / Ubuntu 18.04 LTS / Ubuntu 20.04 LTS / Ubuntu 22.04 LTS / Ubuntu 24.04 LTS / Ubuntu 26.04 LTS / Ubuntu Pro Realtime 24.04 LTS : libx11 vulnerabilities (USN-8913-1)

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-3179 advisory.

    A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap     overflowing the key_sym_map. (CVE-2026-88806)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of libX11 installed on the remote host is prior to 1.6.7-3. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3977 advisory.

    A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap     overflowing the key_sym_map. (CVE-2026-88806)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4501-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4502-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4500-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 45 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-0072911d9d advisory.

    xkb: Check the keysym range in _XkbReadKeyActions (CVE-2026-88806)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-0d57b0d529 advisory.

    xkb: Check the keysym range in _XkbReadKeyActions (CVE-2026-88806)

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap
    overflowing the key_sym_map. (CVE-2026-88806)

The remote SUSE Linux SLES12 / SLES_SAP12 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:4410-1 advisory.

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).
    - CVE-2026-94283: out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser     (bsc#1281653).
    - CVE-2026-94284: out-of-bounds read vulnerability in libX11's XIM trigger-keyregistration     parser.registration parser       (bsc#1281657).
    - CVE-2026-94285: out-of-bounds read in libX11's byte-oriented codeset parser (bsc#1281661).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has packages installed that are affected by a vulnerability as referenced in the openSUSE- SU-2026:21908-1 advisory.

    This update for libX11 fixes the following issue:

    - CVE-2026-88806: XkbGetMap Reply Heap-based Buffer Overflow (bsc#1280910).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap     overflowing the key_sym_map. (CVE-2026-88806)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
365230	Amazon Linux 2023 : libX11, libX11-common, libX11-devel (ALAS2023-2026-3179)	Nessus	Amazon Linux Local Security Checks	Local	high
365182	Amazon Linux 2 : libX11 (ALAS-2026-3977)	Nessus	Amazon Linux Local Security Checks	Local	high
363081	SUSE SLES15: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4501-1)	Nessus	SuSE Local Security Checks	Local	high
363066	SUSE SLED15: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4502-1)	Nessus	SuSE Local Security Checks	Local	high
363064	SUSE SLES15: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4500-1)	Nessus	SuSE Local Security Checks	Local	high
362924	Fedora 45 : libX11 (2026-0072911d9d)	Nessus	Fedora Local Security Checks	Local	high
362836	Fedora 44 : libX11 (2026-0d57b0d529)	Nessus	Fedora Local Security Checks	Local	high
460146	Echo: libx11: security update to 2:1.8.12-1+e1	Tenable Cloud Security	Echo Local Security Checks	Local	high
460146	Echo: libx11: security update to 2:1.8.12-1+e1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
362573	SUSE SLES12: libX11-6 / libX11-6-32bit / libX11-data / libX11-devel / etc (SUSE-SU-2026:4410-1)	Nessus	SuSE Local Security Checks	Local	high
350148	openSUSE 16 Security Update : libX11 (openSUSE-SU-2026:21908-1)	Nessus	SuSE Local Security Checks	Local	high
349072	Linux Distros Unpatched Vulnerability : CVE-2026-88806	Nessus	Misc.	Local	high

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